Electromagnetic Interference Effects Based On Graphene Surface Plasmon Polaritons

Surface plasmon is a kind of collective oscillation formed by the interaction of electrons with incident electrons or photons on the surface of metal.Since the plasma wave can overcome the traditional light diffraction limit,there is a huge local field enhancement,abnormal transmission,great emphasis lies on the application to sensing and biological detection.Graphene,as the star of material fields,has always been favored by researchers because of its unique thermal and electro-optical properties.It is exciting that the researchers found out that graphene supports the propagation of surface plasmon and was experimentally confirmed in 2012.Combining the excellent properties of graphene materials and potential applications of surface plasmon polaritons,research on graphene surface plasmon polaritons has gaining its popularity in recent years.Based on graphene surface plasmon polaritons,plasma transparency and absorption effects have been studied in this paper.The main work and results of the article are as follows.(1)we have designed a novel structure of graphene metamaterial capable of realizing plasmon induced transparency(PIT).The specific structure is made of graphene rings(as a bright mode)and graphene ribbons(as dark modes)periodically arranged.We study the PIT effect from numerical and simulation aspects with finite difference time domain(FDTD)method.We have studied the formation mechanism of the PIT effect.It is found that the ring acts as a bright mode(dipole)and acts as a dark mode(quadrupole)to form PIT.The two-coupled oscillator theoretical model is employed to well explain the formation mechanism of the PIT effect and the analytical result shows good consistence with the numerical calculations.There are two ways to control PIT in our system: changing the structural parameters and changing the Fermi energy of graphene.At the same time,we studied the slow light effect of our structure.The group delay over 0.03 ps is equivalent to the distance of light entering 9um in vacuum.Focusing on the sensing performance of our system,it is found that a higher RIU can be achieved.The change of refractive index corresponding to the resonant wavelength of each unit(RIU)can reach 4833 nm/RIU.The structure we design has great potential applications in slow light devices and sensors.(2)we realized the plasmon induced absorption effect(PIA)in three dimensional graphene waveguide system.Our waveguide system consists of two graphene rings and two graphene bus waveguides.Similarly,we have studied the PIA effect of graphene waveguide system by finite difference time domain(FDTD)method.We have studied the formation mechanism of PIA by changing the gap between two graphene rings.The extreme destructive interference between two propagation pathways |1>-|2> and |1>-|2>-|3>-|2> contributes to the realization of the PIA window.For the consideration of application,the phenomenon of double induced absorption peak is realized by adding a circle.The formation mechanism is also the destructive interference between two propagation pathways(|1>-|2>-|3>and |1>-|2>-|3>-|4>-|3>).We have studied the effect of structural parameters on PIA.It is found that the PIA spectrum has obvious red shift along with the increase of the radius of graphene ring.Without changing the structural parameters of the system,we can only change the Fermi energy of graphene,and we have achieved the PIA effect of active control.At the same time,we have done a thorough research on the sensing performance of the system.Our graphene waveguide system is very sensitive to the change of refractive index in the surrounding environment.The change of refractive index corresponding to the resonant wavelength of each unit(RIU)can reach 8800 nm/RIU.The waveguide system that implements the PIA effect has important research significance in optical switches,optical circuit devices and sensors.